1. Field of the Invention
The present invention is broadly concerned with improved daily ration feed products for animals including minor amounts of an active such as a pharmaceutical drug. More particularly, the invention is concerned with such feed products, and methods of preparing and using the products, wherein the feeds contain a sufficient quantity of an active so that when the animals consume the feeds, therapeutically effective amounts of the active are established and maintained in the bloodstreams of the animals. In this way, conventional dosing regimes are eliminated, and the animals receive proper quantities of active as a part of their normal daily diets.
2. Description of the Prior Art
In recent years there has been a significant increase in animal research directed to determining proper nutritional standards and also effective drug treatments for animals. This is true not only in connection with domestic household pets such as dogs, cats, birds, and exotics, but also in regard to economically significant animals such as farm animals (e.g., horses, sheep and cattle) and zoo animals of all types.
Insofar as drug or active treatment of animals is concerned, it is generally required that these agents be administered from time to time by oral administration or injection, so that therapeutic amounts of the actives or drugs can be maintained in the bloodstreams of the animals either continuously or at least during a prescribed treatment period. Periodic dosing presents a number of difficulties. For example, the animal's caretaker may simply forget to administer a given drug or active at the required time. This can have the effect of disrupting a treatment protocol and even causing harm to the animal. For instance, dogs are conventionally treated with heartworm preventative drugs such as ivermectin on a monthly basis. If the dog's owner forgets to timely administer the drug, the dog is susceptible to heartworm infection. Another problem associated with periodic dosing of animals stems from the fact that the animals may be very reluctant to cooperate, especially if the drug or active is to be orally administered. Any cat owner can testify to the difficulty of persuading a domestic cat to consume a drug product.
Attempts have been made in the past to provide daily ration products which include therapeutic drugs. For example, Hills Pet Food Products made and sold a Science Diet product referred to as “Maximum Stress Diet” which included small amounts of styrylpyridinium chloride and diethylcarbamazine in a canned dog food containing substantial quantities of animal fat which required refrigeration. However, the Maximum Stress Diet is no longer available, and was not optimum in that it required refrigeration and special handling. This is to be contrasted with conventional extruded feed products designed to be stored over extended periods at ambient temperature without significant loss of nutrients.
U.S. Pat. No. 6,190,591 describes a single-extruder process for the production of controlled release particles which may be tableted. Various encapsulants including pharmaceuticals, nutraceuticals, nutritional compounds, biologically active components, flavorants, fragrances, detergents and surface-active compositions are described, at relatively large quantities in the particles of at least 1% and preferably from about 3–50%. Hence, the '591 patent is not concerned with complete feeds, but rather encapsulant particles. The process described in this patent make use of an elongated extruder where water and lipid are successively injected into the barrel, followed by water evaporation from the barrel and final addition of encapsulants. Such equipment is generally not suited to the production of a daily ration feed or similar product, given the need to uniformly distribute an active in the latter type of product.
There is accordingly a need in the art for improved daily ration extrusion-processed feeds and methods of providing actives to animals in a manner which will avoid problems inherent in periodic dosing, while maintaining substantially constant therapeutic levels of actives in the bloodstreams of animals consuming the feeds on a daily basis.